With the increase of bandwidths, methods for implementing service convergence at the electrical layer (the typical method is via a multi-service transport platform (MSTP)) become more and more expensive due to the use of a lot of transponders. Thus, the metropolitan wavelength division multiplexing (WDM) technology is extensively used. However, the wavelength bandwidth is rather large for the mainstream applications at present and in the coming years. Thus, when the wavelength is used to carry new dynamic services such as the Internet Protocol Television (IPTV) service, the bandwidth utilization is low.
In the prior art, a sub-wavelength optical switching technology similar to the optical burst switching/optical packet switching (OBS/OPS) is able to provide service convergence and switching at the optical layer. It is applicable to the transmission of dynamic services of sub-wavelength granularities, and may help to reduce the quantity of transponders and lower the cost.
Optical burst ring (OBRing) means that the OBS is introduced in a ring. Because the ring network has a simple topology and a single service flow direction, the middle data processing node of the OBRing does not need to perform complex switching. In this way, the OBRing may avoid contentions and conflicts. In addition, because the OBRing reserves the ability of the OBS to provide small-granularity service convergence at the optical layer, the OBRing can carry dynamic services including IPTV in a cost-effective manner, with a better application prospect.
In the prior art, the OBRing solution is an Ethernet-based OBS solution. In this solution, a fixed-wavelength receiver and a wavelength tunable transmitter are used, and a fiber delay line (FDL) array is set on each data processing node to synchronize the control channel with the data channel.
However, in this solution, each data processing node forms a receiving tree, and different receiving trees (that is, different data processing nodes) do not share the bandwidth. Thus, the resource utilization is reduced.